Green’s Dictionary of Slang

1. (UK Und.) the act of pulling up the lining of a pocket until the purse it contains is within reach.

1865		Leaves from Diary of Celebrated Burglar 70/2: Before her clouts had reached the ground they were on my arm, and a couple of ‘reefs’ brought the ‘poke’ within my grasp.
1949		Monteleone Criminal Sl. (rev. edn).

2. (Aus.) a punch.

1983

J. Byrell (con. 1959) Up the Cross 10: ‘Awful reached out and gave him a reef up the orchestras’.

3. in ext. use, a feel.

2011

J.J. Connolly Viva La Madness 306: I try on the outfit [...] with her having a reef around [...] getting tactile adjusting the tie.